I've heard of that collection, the guy hasn't advertised a price before. Me, I'd love to have a GT so I'd have a pair of bookends.
Maybe one of these days...
GT's share pretty much every exterior body panel and chrome trim part with the 'vert with the exception of the obviously changed ones. The biggest engine difference is the catalytic converter and cast iron exhaust manifold, otherwise it's garden variety 907 Lotus right down to the Stromberg carbs. They used the same 5 speed Getrag that was used in the JH5. It has power windows, rare in that time period. As a rule, the US market GT's had A/C, at least I've never heard of one that didn't. The padded part of the dash is super rare but there's a guy in Cali who rebuilds them, and were it me I'd buy the least rusty one I could find.
BTW Dan, that's not a wagon. It's a shooting brake.