Well in Vancouver with covid 450 wouldn't be unheard of for an asking price. Not sure if they're selling at that price but I have seen some nice cl listings disappear at around the 400 mark. Prices are all over the place. Doesn't really matter what quality the bike is, it's just plenty of people asking hundreds of dollars for bottom end bikes. This one probably better quality, so that's something. Pictures or links would be great as they will help others form a better opinion.

If it's been in the shed for 20 years, you'll probably want to keep in mind it might need some service and replace the consumables. The cost for that might not be entirely trivial, especially if you need someone else to do it for you.