wow, a GTS-1! someone would surely get that for his collection. looks like it was well taken care of. i am always on the look out for cheap obsolete survey equipment for my collection. that guppy is old enough for someone to collect.
Early in my party chiefing days I was tasked to topo about 200 acres of anything but flat ground and my employer's total station had been damaged and they told me I'd have to use their Guppy. No data collector. I ran that Guppy and booked every bleepin' angle and slope distance for every traverse/topo shot and reduce every shot by hand, hundreds and hundreds of shots, day after day. If I never see another Guppy again it will be way too soon. I suggest using it as an anchor.