I just checked the Canadian IMP section of the web site and shame on me for not having any pictures up of the Wornick parts. But...
Wornick does (or did) produce at least some of the entrees for the IMPs. I've had a few IMPs that were from Wornick. They're the same size and shape as the Freddy Chef IMP entrees.
Was there anything in your IMP that was from Wornick? What else looked like it was from an MRE or RCIR? Sadly, I haven't had any new IMPs since the 2001/2002 batch I currently have.
About 5 years ago or so I found my first (and so far only) IMP at a gun show I was rooting around at. When I got around to opening it I was surprised to find what appeared to be an MRE desert component inside of it --- a Sterling Bakery Pound Cake.