Pentax made some great stuff back in the day. If I recall, those older ones were able to operate even without a battery. That one looks great for a thrift shop find. I bet you got it for cheap.
Correct.
The battery served only two functions; Operate the Metering System and for the sync to the Hot Shoe for your electronic flash. But if your battery went dead all you needed was a small, inexpensive, hand held light meter and you were good to go on Manual.
I have a small Meter - 'somewhere' - that could slip into the Hot Shoe. It's about the size of a Zippo Lighter. It's a Vivitar (iirc) and I paid about $20.00 for it 'way back when' and not being able to find it now is driving me nuts. I have a whole bag of 'stuff' that went 'missing'. A mini tripod's in there, various 'speed lights' I bought, shutter release cables, lens filters, and that light meter.
(1) I'm 99.95% sure the wife put that 'extra' Gadget Bag in the Crawl Space and that's like entering a Black Hole. For my stuff anyway, her stuff she can always find. Not that I'm complaining :-)