It's a proper old one.
Given the size of the DOL starter on the front compared to the width of the body, I'd say it's the single motor, 10"x7", P/T model.
The MB is a 12" and the CP is 16". That's a massive machine and I wouldn't expect to see one sitting on a set of castors.
The PTs that I've seen all had a fixed outfeed.
Inspect the screw that raises and lowers the infeed table. The thread can be rough and chewed up if it hasn't been maintained.
Wind the thickness table from top to bottom and back to be sure it's smooth. There's a pair of helical gears underneath the big bottom casing.
Take off the back cover and check the chain and sprockets for wear. Like on a pushbike, worn sprockets become sloppy / shallow with sharply pointed teeth
Spin it carefully by hand. The PT has a single motor driving both a v belt for the cutter block and a flat belt to a chain. There's a spring tensioned arm halfway up with an intermediate pully / cog. Make sure this whole unit moves smoothly with no clicking and no contact with the edge of the belts. I've only renovated newer models of the PT than this and when those are serviced it's quite easy to fit the idler cog the wrong way round during reassembly.
Assume with something old like this that you'll need to replace the cutterblock bearings and probably the bronze bushes at each end of the infeed and outfeed rollers.
Check the toothed feed roller to make sure it's not worn out.
Take out the blades - not because they matter, but so that you can look at the block, the wedges and the grub screws that adjust and clamp the wedges. Most importantly the screw threads in the block need to be OK. It's very exciting when a blade is spun out by centrifugal force and whips around to smash into the lip of the infeed table. Occasionally you see a planer which has had the infeed table machined and a new "lip" bolted on. It's not a replaceable wear part, it's a repair job
Oh, and is there an extraction hood with it ? I think new ones from Sedgwick were running about £260 last time I checked.