Which Fox 049 do I have?

I own two Fox 049 engines. I know I have an FAI, but I have a box for a regular 049. I have one of the engines in hand right now. Don't know where the other one is. I have what I think is a simple question. Which one do I have in hand? Specifications won't be much help. I need external differences. The one I have the prop is held on with a cone with holes. It requires a wire of correct diameter to tighten. I thought I recalled the regular 049 used a prop nut, but it has been many decades and my memory often betrays me. I also thought i remembered the regular 049 had a funky starter spring. This engine does not have one. This one has an attached tank. The identifier on the crankcase does not specify FAI 049. It just says Fox 049. So, what do you think? FAI or regular?

I know of no Fox .049 that came with a starter spring. The other problem with prop nut vs screw is that the standard Fox .049 used both. However, the FAI used a spinner nut. The single most important factor is that the standard .049 has rectangular cuts in the cylinder whereas the FAI version has angled cuts in the cylinder.

https://sceptreflight.com/Model%20Engine%20Tests/Fox%20049%20FAI%20Special.html