I don't know whether mixing 335's and 345's was standard practice, but I very much doubt it.
The 335 I'm referring to is the (only) factory black '59. The FON is definitely correct, and it has the early varitone choke routes......but was never fitted with a varitone. It also has single ply binding on the top, unlike a 345. It was redesignated from 345 to 335 in the ledger and on the orange label too. Make no mistake, however, this guitar left the factory as a 335. It was also shipped later than most in the same FON, October 59 in this case, which is late for a first rack, although the black 345s also have serials that suggest they were shipped somewhat later than they were made.
The 335 I'm referring to is the (only) factory black '59. The FON is definitely correct, and it has the early varitone choke routes......but was never fitted with a varitone. It also has single ply binding on the top, unlike a 345. It was redesignated from 345 to 335 in the ledger and on the orange label too. Make no mistake, however, this guitar left the factory as a 335. It was also shipped later than most in the same FON, October 59 in this case, which is late for a first rack, although the black 345s also have serials that suggest they were shipped somewhat later than they were made.