Oh my, I can't believe what I am about to type. I'm going to contradict juvela .

I don't think it is a Windsor International because I had an International and from my memory, which may not be that great, it did not have fast back seat stays, it had the serial number on the seat tube rather than the lug, it did not have holes in the bottom bracket and the lugs don't look the same.

I will say that I got the same Windsor/Acer Mex vibe but, if it is it is a Windsor/ Acer-Mex then it would be up a model or two from the bottom end International. Carrara maybe?