Having looked at this forum and at pics and ads online, I can only conclude that I was incredibly lucky to have found three successive natural-finish T-40s with rosewood fingerboards (and equally unlucky to have had them stolen!) . Interestingly I took my second T-40 to America with me in July 1983 for two months and got invited to a jam session where somebody had the matching T-60 guitar!
Is the natural finish/rosewood board a particularly rare combination, and were they exported to the UK in greater-than-average numbers?