Used cap identification

I just purchased a used aluminum cap for my tacoma and the seller -who had also bought it used- had no idea of the make. I've scoured it for anything that might give me clue and can't find a thing- no serial number, marks or stamps of any kind. Seller didn't have keys and I'd sure like to get a replacement set rather than buying three new handle assemblies. The stock handles are nice quality. Any suggestions of what I might be missing?

 

Posting pictures will help with IDing it. If it's aluminum I'd guess it could be a commercial style cap. But who knows. Also if you have a large cap dealer in your area they may be your best resource for IDing it an getting parts.