Sometime in the summer of 1972 the majority of Wicked Lester’s equipment was stolen from their rehearsal loft on 10 East 23rd Street. Paul and Gene were still focused on the preliminary deal they had with Epic and, as we know, they had started looking for new musicians for a new incarnation of Wicked Lester. Obviously they needed new instruments. "When we [KISS] first got together, Charlie LoBue had a shop in New York called Guitar Lab and he used to make some wonderful Instruments." (Guitar Player 1978) In KISStory there is a Guitar Lab receipt shown with the date 9/15 (or 13) and my best guess is that this was when Paul bought his Doublecut. (Even though the year isn’t visible the receipt can’t be for his later LoBue Custom V, the month isn’t right.) So when the band that would become KISS started rehearsing as a three-piece Paul had "graduated" from stock guitars to a hand-built LoBue Doublecut.
The Doublecut that Paul bought looks very similar to the custom one built for John Gatto of the band Good Rats around the same time so I'm going to assume that the specs were at least similar. (Just like Gene, Paul has referred to his Dooublecut as "one of Charlie's stock models" but also claimed that it was custom-built.) Actually, most of the known LoBue Doublecut guitars from this time had bodies and necks of mahogany and an ebony fingerboard so I assume Paul’s Doublecut used these same materials. The Doublecut also had creme binding on the front, neck, and headstock. The bridge/tailpiece combo was probably a Gibson. We have no photos of Paul's guitar showing the bridge well enough but LoBue was using Gibson parts a lot. Paul has suggested that the pickup could have been a DiMarzio: “I would almost bet that the first pickups in my Guitar Lab guitar, which Charlie LoBue made, were DiMarzio pickups." (Vintage Guitar March 1997) It is true that Larry DiMarzio worked for Charlie LoBue under the guidance of Bill Lawrence in the early 70s and it was under the tutelage of LoBue and Lawrence that DiMarzio began development of what would become the legendary Super Distorsion. But he didn't come to work for them until 1973 when the Guitar lab had moved to the 206 Thompson shop. (That said, this is all a long time ago and the move to 206 Thompson could have been made earlier.) The LoBue Doublecut makes its debut in Paul's hands at the showcase for Epic in late November 1972.
The LoBue Doublecut was probably used for the very first show the band played at the Coventry on January 30, 1973. The photos taken by Lydia Criss doesn't show much but there has been no mention of any other guitar from those days. In the backstage photo from the March gigs at The Daisy we see a guitar that seems to match the Doublecut from late 1972.
Unfortunately The Doublecut LoBue wouldn't stay in Paul's possession for very long. In the summer of 1973 it was stolen: "At our first show we did as a New York band with The Brats and Wayne County [...], at the end of the night in the thick of everything going on [...] the guitar got stolen." (Metal Edge presents KISS Alive 1996) Considering the details of this anecdote that would be the show on May 4, a date which KISS Alive Forever also identifies as the time the LoBue got stolen (see p. 18-19) as do several quotes from Nothin' to lose by Ken Sharp. Eddie Solan: "Paul and Gene had matching custom-made bass and guitar, which was made by a Manhattan guitar maker named Charlie Le Beau [sic]. Somebody stole Paul's guitar that night and he was devastated." The only photo from that show that I know of (that is usually improperly dated as the June 1 show) doesn't really show what guitar Paul is playing but the Les Paul that Paul got and played for the remainder of the year had binding on the back which the guitar from the May 4 photo doesn't. According to Paul "It was a shock but not a big setback. [...] It didn't matter, your guitar was gone, buy another one and keep rockin'." (Nothin' to lose)
Knowing this we have to address a claim made by Paul: "On the first album, I was using a custom-made guitar by Charlie LoBue, who at one point worked for Dan Armstrong in New York. Then, he started his own place called Guitar Lab. He made my first custom guitar. It was really based on Gibson principals. It was kind of like a double-cutaway with binding on the front and two humbucker pickups. […] That [guitar] was stolen before we went on tour after the first album was done". (Vintage Guitar March 1997) Paul most certainly did not use the LoBue Doublecut to record the eponymous first album, that job fell to the 1973 Gibson Les Paul Custom ’54 Reissue.