I have recently purchased a Merlin mountain bike frame with the serial number in the rear dropout 2557. Merlin has a curious hole in its memory for frame numbers:

1989 serial numbers end at 139
1990 serial numbers start at 3518

I presume mine was fabricated in 1989, but have no further information.

Here are some images of the frame.

Any information on the history of this frame? Any thoughts on how to rebuild it?