Eastman Home Portrait back question

I have an 8x10 Eastman Home Portrait No 3 camera which I have been cleaning up. I've started on the back first and noticed something interesting. There are 1/8" grooves on opposite sides of the back in the part that would be between the film holder and ground glass. The adjacent sides are at different levels, and one side each has some spring steel. Does anyone know what was supposed to go in these grooves?

Also, does anyone know how the wood on this camera was originally finished? I saw a reference to Walnut stained Cherry but there appears to be something applied on top of that. The one I have is very dark and I don't know how much of that was intentional and how much of that is due to age. The brass fittings have a lot of tarnish but are polishing up nicely.

-Darren

These grooves are for wooden splitters so that one can make 2 - 4x10's, or 2- 5x8's, or 4 - 4x5's on a single sheet of 8x10 film. One of each pair should have spring in the groove so the splitter can be pushed against it for insertion, and the spring tension keept teh board in place.