Old 5/16" pneumatic stapler

[PoppaSki]

I bought a used stapler the other day, not sure if it qualifies as vintage but it is old. It's all metal construction, used to be red, and it has an "S" inside a pentagon on the handle near the air fitting. I can see no other markings. I'm guessing it was made in the 90's.

Can anyone help me identify it, age or model etc.?

I would love to post an image but my post count is too low.

Thanks,
Dwayne