This is the Master List for Reatta ECM PROMs.
Interesting to note, all model years had changes during production. Only 1988 and 1989s are known to have a TSB issued for them. It's also interesting to note 1989s didn't get the final version of their PROM until its production was over so none left the factory with it.
Information on how to check the ECM PROM ID DATA (ED99) can be found here: Reatta Onboard Diagnostics Booklet on page 6.
YEAR - EMISSIONS - ECM EPROM - [LATEST VERSION] PROM ID (DATE RELEASED) - OLDER PROM VERSIONS
1988 - ALL - [ANCX 3534 (6-88)] - ANBM 2544 (12-87), AJSF 8674 (4-87)
1989 - FEDERAL - [ASSU 1094 (10-89)] - APTN 2204 (8-88), ANNH 5784 (5-88)
1989 - CALIFORNIA - [ASSW 1104 (10-89)] - APTP 2214 (8-88), ANNJ 5794 (5-88)
1990 - FEDERAL - [ATYH 8064 (9-89)] - ANWU 9044 (6-89)
1990 - CALIFORNIA - [ATYJ 8074 (9-89)] - ANWW 9054 (6-89)
1991 - FEDERAL - [AXMX 1484 (11-90)] - AWRH 6724 (6-90)
1991 - CALIFORNIA - [AXMY1494 (11-90)] - AWRF 6714 (6-90)
Thanks to MC_Reatta, member of the Reatta forums, for this information.