Thanks for adding a new lens to our gallery and thanks also for your series of PMs helping me to understand exactly which variant of 75-300mm lens we were discussing. One of those PMs included a photo of the front of the lens which clearly shows the name as EF 75-300mm 1:4-5.6 IS
so, from the Canon Camera Museum
, as there is only one variant of 75-300mm which includes IS then I think this must be the EF 75-300mm f/4-5.6 IS USM
and that lens is a piece of Canon history as, from that page
This telephoto IS (Image Stabilizer) zoom lens is the world's first interchangeable lens for SLR cameras that incorporates an Image Stabilizer
That lens was only superseded in 2005 (by the EF 70-300mm f/4-5.6 IS USM
) so I guess the chances of your lens being once of the early ones are slim but it's still really nice to see this lens showcased here on the forum. Thanks for sharing.