Some of the best quality recorders around that era were quartz controlled disc driven to maintain proper speed in the tape mechanism. Favourites such as the Sony WM-D6 and D6C had this and are now legendary in the bootleg world. The WM-D6C still provides high quality audio today and matches any hi-fi separate deck, hence the price on the used market.
So in answer to your question (!!!) yes, it probably is fast and many bootlegs around this era aren't at their proper speed unless recorded on one of these machines (or equivalent).
