1990 Olds Cutlass A/C help needed (ecm?)

1990 3.1 v-6 non-California, auto (4 spd) with cruise. Took it in to get A/C fixed. Jumpered and found bad compressor. Was told it has a full charge of R-12, but compressor won't kick on. All switches good according to him. He says even changing compressor will not get it to work, as ecm may be bad. I put a used ecm in about 3 months ago, for a bad running engine problem. I did not change the prom chip, as the salvage yard guy said all I would have to do is match up the last 4 or 5? numbers on ecm that I pulled from a similar vehicle. My question is, do I need the original prom chip (gone, in trash), or another ecm from exact year,model,options, etc., or is there a place I can get another prom chip?

Wife is not happy without A/C, and if momma ain't happy, ain't nobody happy>