I just bought one of the 124 storage box arm rests (like the pic below, but it's blue) in a junkyard last weekend. I got it and several other things for $35. So you should be able to find one for pretty cheap. I'm going to try to retrofit it into my 123. If it looks like it won't fit I'd be happy to sell it to you. Shipping my cost an arm and leg though.

__________________