I found this one some time ago thrown out and I grabbed it. It is a 1980 model. Was missing one attachment which I got at the time for no charge from Actron Mfg. They made "161" model prefix product for Sears and also "244" was Peerless Instruments which they bought circa 1983.
Actron has since been sold and I believe they have gotten "amnesia" on the old stuff.
I also have a 1981 (or so) engine analyzer still in the box (but lightly used) that my dad bought, and a 1985-1986 "dual version" (digital and analog) analyzer that I got off Ebay.
All are "161" branded product as well as my Craftsman timing light with advance function.
Actron has since been sold and I believe they have gotten "amnesia" on the old stuff.
I also have a 1981 (or so) engine analyzer still in the box (but lightly used) that my dad bought, and a 1985-1986 "dual version" (digital and analog) analyzer that I got off Ebay.
All are "161" branded product as well as my Craftsman timing light with advance function.

that's a lot of info..I think you are right, the timing light is the non advance.