Didn't everybody rave on about these things. Bargain if it's really what he says. And will post as well
Love the look of a big tubed raw alloy polished Zaskar. I don't think there are too many cooler and burlier looking alloy HT's. The earlier US made models (around the 1992 era) are the more sought after ones. I've never had one and any alloy HT I've ridden felt too harsh to me.
You have to know what you are buying though. GT made a load of very similar looking Taiwan made alloy HTs like the Avalanche, Aggressor and Pantera to name a few. Sly gronks have re-stickered and stripped the lesser models as Zaskars to get more $$$.
From memory, the US made Zaskars have flat top tube end caps only - the Taiwan alloy HT are curved. The US zaskars are 6061 (it is stamped on one of the rear dropouts) while the other alloy HTs are 7075 which is also stamped on the dropout. Early Zaskars only had a U Brake mount too.
Those sketchy small but long distance photos in the Gumtree link always make be suspicious. Is it 'that' hard to take a decent photo with any camera these days? ...Gee. The head tube is recessed at the top and bottom, the top tube is hydroformed and can't tell if it gussetted. Looks like it has panniers mounts on the rear stays. It might be fine enough project frame for the right $$$ but not an uber Zaskar model from what I can tell so far.
This the one that the GT aficionado's sell their kidney's and first borns for.
https://veloaficionado.com/blog/1992-gt-zaskar-20-handmade-in-usa-6061-t6-aluminium