My son's has surge brakes and I thought all Demco's came with them. Could be wrong..it happened once before

Check the top of the hitch for a half dollar sized plastic cap. That would be the cap for the master cylinder. If it has brakes, they will probably need to be gone over. We just purchased complete units from etrailer and replaced everything. Easy and cost effective. Easy enough to tell. Just pull a wheel and look for brake drums.
There are no shocks, but there is a steering stabilizer that is just behind the main frame and lies horizontally.
The bearing on ours are sealed and do not require, nor is there any way, to service them. Grease your "tie rod" ends and the spindles and do it often.
When in use, you pull a pin which allows both wheels to turn in unison. Ours does not have pivoting pads like most dollies. We could not find a SN on ours. There was a decal with, I suspect, model and serial number on the left side of the main frame, but it was so faded that we could not get any info from it.