am i supposed to vote for the old musty smell?

anyway, how long have you had it in your possession? if it was in a damp place it probably needs a good bake in the sun, (not oven). if it doesnt improve in breezy dry air in a couple days i'd set it aside for a few months in a dry spot and reconsider it another time.

that musty smell is mold. you may want to find out what kind of mold before you bring it into your home. if you see any black or greyish parts throw it out. there are anti-mold chemical treatments but they are pretty bad for your health and almost never work. drying it out will kill the mold but not the spores, so if it's a dangerous mold you're just going to spread it around the house and you'll end up ripping out a bunch of your walls and flooring in 5 years. So make sure it's not a dangerous mold.

Mould/mildew can be killed with UV...but the spores are hard to get rid of. Painting will detere the continuation of growth...but I would not want to bring something into a 'clean' home like this. Once mould gets a toe hold, you are looking at thousands of dollars of remediation...all for the cost of an antique window.

the only product I would recommend for treating mold is giving it a a cavicide bath. it's a protease which should break down the chitin in the mold but not the cellulose in the wood. I don't know if it is available to the public though.