+1 on 75slant6's comment. Watch out for Cherokees too, I think a lot of them had security. Maybe you could google the PCM part number and get some answers on what it came out of.
If it turns out you do have a security PCM... well, before I make my next suggestion, let me say I hate Facebook groups for car advice. The nature of posts and comments for responses isn't great, I think a forum is much better. But there aren't a lot of guys on FABO that have done the EFI Magnum swap (certainly not as many as there are that could help you with just about any other Mopar related question). The Magnum EFI swap group on Facebook has a bunch of guys that know what they're talking about, so if you're not already a member you might want to join it. I searched through some old posts about the security issues and saw some responses, so you might be able to find the answer without posting a question of your own.