Wow,yes its a collection piece.You can still get batteries for it that are aftermarkets.
HT90 was a good reliable radio back in its day in early to mid 1980s.I have a customer who still has 7 of them in service for now.
The HT440 was similar radio but came in 6 channels and used alot of same parts for repair outside of the board.
I had boxes of them during a Motorola trade up program in 2004 or 2005.Most worked and just needed a new battery.We donated them to local
Boy Scout troop.