... And if it does, what does it translate to?

www.teanglann.ie mentions it could mean to treasure a possession (if I'm looking at the context correctly):

https://www.teanglann.ie/en/eid/is_luachmhar_le

Another example from: http://www.potafocal.com/beo/?s=fuisce
gives the sentence: "Is luachmhar liom na laethanta sin"

Could it mean "I treasure these days"?

I think you can post all your questions under one topic. Do you mind if I merge all your requests into one post?

Well, a phrase you can read in a dictionary obviously exists.
is luachmhar liom é = I treasure it ("It is precious in my opinion")



Yes, it does mean exactly this.