There is a way to identify a memcal by the knock sensor board. Under the clear sealer is a code in purple, blue or black ink. I don't have a complete breakdown of the code but the second or second and third letters will identify the engine the ESC board was designed for. I have a partial list started by Ludis Langens and added to by myself and a man going by "pontiacjeff" on a few forums.

A is for 2.8L 60 deg V6
B is for 2.0L Turbo Sunbird
C is for 2.3L Quad 4
G is for 3.8 Buick V6
H is for 2.0L Turbo Sunbird
J is for 3.1L 60 deg V6, both NA and Turbo
K is for 3.3L Olds V6
R is for 5.7L TPI
V is for 3800 Buick V6
*or*
05 is for 3.3L V6 Olds
09 is for 3.1L V6
14 is for 4.3L V6 (Turbo)
19 is for 4.3L 90 deg V6
35 is for 3100 V6
36 is for 3.4L 60 deg DOHC V6

You guys with the later TBI trucks have a chance to check a few memcals and maybe add to the list. We'll need a few to compare to make sure there's a pattern. I have a BJYA memcal which has a 26. A post in another thread lists BJYL with a 26, along with BNKM = 34 and BDYT = 16. The more data we can get together, the better our skills when we're out at swap meets & etc.