An interesting question - I've owned it since new, and nothing has been changed. I grew up in Scotland loving jazz from a very young age, and wanted nothing other than to be a drummer with a Gretsch kit, 'cos all my idols played Gretsch, and ideally it had to come from Manny's in New York, which I saw as the greatest drum store in the world!
Took a few years, but eventually I achieved both ambitions and bought this kit in 1971 when I was sailing out of Miami on the SS "New Bahama Star" in the pioneering days of cruising. I only bought the 3 drums, though, as I much preferred the Ludwig snare, which I bought at the same time.
(I also chose a Ludwig Speed King pedal, Slingerland Hi-hat, and Ludwig stands, all of which I still have)
The kit, then, is totally original, and whilst I can't quite state categorically how it came to have that particular Tom-Tom mount, (I enjoyed a drink in those days!) I believe it came already fitted, and is therefore Gretsch, as I'm quite sure that had I been given the choice, I would have chosen the Slingerland Set-o-Matic, which I always thought was the best designed, most flexible and beautifully engineered of all. I have a vague memory of being quite upset when the Bass drum turned up with the rail consolette already fitted. for that reason, it could only have been Gretsch, and although it has 4 x fixings, I read somewhere that for a very short period in the early 70s, Gretsch did indeed fit a four hole model, similar to the Ludwig.
I've posted a couple of photographs, and would point out that the hanger for the tom tom has a rounded end, whereas the Ludwig was conical. Also, the knurling is different, but above all the fitting on the Tom-Tom speaks for itself! Maybe I've something even rarer than I realised …
The Bass drum and 14" have lost their labels, but the 12" still has it clinging on - see photos …..
https://picasaweb.google.com/116410754577390367293/RobbieSKitRestorationProject
Robbie