Can I have a date for the advert, saves me looking it up.

From my scope collection there seems to be several front glass colours. The same model might change over the years depending on what price point they were trying to retain. The usual is a grey blue. However there are all kinds and one of my favourites is a bright deep blue as found on the better Tascos. Simons has green blue. Others crimson. Optimas did several; think they were made by Hakko. Hakko has a red dot reticule in the late 70's and charged a premium for them!

In terms of Optimas my all time favourite is the early 4X40 7059 which has the cheaper grey blue, but being fixed with a medium plex is perfect for no faffing farmyard range shooting. Have them on two FWB Sports. The other classic is the original Moonlighter. I prefer it without OA and in truth never really liked the BDC's. The Super Moonlighter wasn't any better at light gathering and far too big. No OA and then they are in focus at 25m on x6 or 7 and at max x9 then 45m!
Optimas with Apel mounts just look the biz on HW35E 80 and 77's plus FWB Sports and Original 45's.

For the early 90's then Optimas couldn't keep up with the competition. Even Tasco had their best and then were to go down hill. Simmons hit the market with their WTC's. Your Optimas was priced similar to Bausch and Lomb and some Leupolds. The former were far far superior and really showed how average Optimas were getting.

Anyhow thats what I think.