Cheap scanner for 1988 Chevy PU truck?
 

Would this be OBD1? Or even before that(?) I've seen good recommendations here for OBD2 scanners but the ones for older cars were particular to each make, if not mistaken. TIA.

That has a flashing light. You need to jumper a connector under the dash and check the lights.

Checking trouble codes for OBD-I (1988-1995 trucks) - ChevyTalk --The Social Network for Chevy Fans

a piece of wire jumpered in the ALDL underdash....

I don't remember the terminals.

I think it is the first two. Is this truck injected? If it has a carb, the computer has very little function .

Yes, TBI with O2 sensor and some type of ECU. It has a plug under dash by parking brake just like a modern car.

If you could pick up an old red brick ( first gen snap on scanner ) that would be the cats meow, would be very useful on other cars through the early 90s as well. Was a pretty good scanner in its day. They turn up cheap all the time.
Snap on Scanner MT2500

GM OBD Trouble Codes –

How to read older GM OBD diagnostic codes for free

Great suggestions, thanks!