Hi all

A couple of years ago I purchased a very beautiful Aria Pro II SB-900 (lined)
fretless bass (as you can see below) and now the time has come to sell it for another purchase.
The thing is that the original owner was dead when I bought it and his son who sold it to me had no idea about music equipment, so when I asked him if the fretless is original from the factory or it was modified later he didnt know.
My questions to you knowledge people is:
-- Are you aware of any fretless SB-900 basses? I havent found any other fretless SB bass. Although, I have to admit that if it is a modified neck the work is so perfect that I cannot find any irregularity in the fretless neck.
-- How much you would estimate ($$) a bass like that? I had checked the serial number and I remember that most probably it is from 1979. The condition is exceptional for its age, with no issues at all and only 1 minor ding on the side. Electronics and PUs work superbly.
Thank you for your time! Any comment is welcome.
Cheers