Well, I'm not saying for sure it's #44 but it seems to point in that direction. Someone could have changed the numbers or stamped new ones that just happened to be really close. Hopefully we'll find out more info soon.
Arthur, I have the same reservation as you about the time gap but I have a possible explanation. Most of the large material pieces for the frames were ordered pre-cut from the tubing supply company. This simplified the frame building process to the point where a batch of frames (maybe 10) was built in a relatively small time frame (nice pun, huh?)
The frames were stamped with the number when the pieces were loaded in the jig for welding. This would mean quite a few numbers would have similar dates. After a body was fitted, the pair would sit on a rack waiting for a customer or their turn in line to be built. A frame could conceivably have been in the shop for a year or more depending on the sales volume and the time to complete the kit or turnkey. When the supply was low, another batch of frame material was ordered and the process would start again with a new group of dates and numbers.
The point of all this rambling is that if David's car is #44 from 1988, it could have been one of the first cars of the next batch; where Arthur's car #42 may have been one of the last from the previous batch.
Jason