The M1225's are narrowband capable. That being said, just because it's narrowband capable doesn't mean it's practical for anyone to use in a commercial environment. I can't tell you how many thousands of radios I've chunked in the trash due to customers upgrading to digital and no longer having a need for the radio (remember most of them had already completely written the radios cost off in taxes so they technically couldn't sell them). As far as keeping them going...in many cases it's not worthwhile to keep a 25 year old radio in operation in this day and age. For one, you have many large radio dealers which have completely removed the computers bench and field techs needed to program and align these radios. In cases where shops can still work on them, you often see "legacy radio" fees to cover the costs of maintaining those now defunct OSes and hardware they run on and by the time it's all said and done a repair can cost more than the cost of just purchasing a new radio.It depends on the vintage of the radio; if I recall correctly the M1225 models are narrow-band compliant, and if so they would still be perfectly good. Best way to find out is run the FCC ID through the FCC database and check the authorized emissions.
If it's still good for narrowband I'm a bit surprised someone would just chuck it in the dumpster. You got a heck of a find; the power supply alone is worth a few bucks.
Pretty sure that power supply "hood" over the radio is just a shell that comes off and leaves an ordinary power supply; if necessary you could pull the "hood" off and use the power supply for other stuff without worrying about fit.
Just as an example, between 2015 and 2019, I didn't do a single Mag One repair because by the time the customer got charged the diagnostics fee, the materials for the repair and the labor to actually perform the repair and re-align the radio...it was the same price to sell them a new Mag One.