Not so easy to tie to a facility, it's all about date of manufacture. Some pioneers and 48's made late in the Singapore run did have painted keys.
FWIW, 42's were not part of this change over, as production of them stopped in 1995. The last batches of service spares built in 2001, in Indonesia, had molded keys. So, they were either built from molded parts already on hand or the molds moved to Indonesia. I suspect it was from parts remaining in inventory.
Also, with very few exceptions, the 10/11/15/16C models had molded keys. Only here in the museum was it documented that some late production units had "painted over" keys, where double shot keys were painted black and then relabeled with a new function. The 12C gold classic has had painted keys for a long time, beginning with production in Malaysia.
Edited: 23 Apr 2012, 7:44 a.m.