....... RE: Googa Mooga records being the 1st bootlegs, I'd have to say no to that.
However, I don't doubt that their 'US sourced releases' could have been put out without the US label owner's permission. Probably the guys who licensed the 1st Eddie Parker were sent copies of his other 'recent releases' by Jack. Jack hoping they would come back to license some of these additional tracks but perhaps they just went ahead & put them out anyway.
In Europe in the 60's (& early 70's), it was NOT UNCOMMON for a US recording to be dubbed off a mint copy of the US 45, a stamper made & UK / French / German label 45's run off (President / JayBoy did this most of the time I'm led to believe).
ALSO, it's my understanding that very little of the stuff released on the UK Sue label from its start up to the mid / late 60's was actually licensed from the US parent companies. The guy running Sue (& I can't bring his name to mind at present) just found copes of US 45's he liked (blues & soul tracks), copied them to tape, ran stampers off, pressed up Sue copies & distributed them to UK record shops.
So, bootleggers came later ........ but not everything that was done by European label owners in the 60's was legal & above board.