Two Small Yemeni (I think) Jambiyas and Questions

[TVV]

Here are two small jambiyas (the smaller is 9 1/2" total), which I think are from Yemen. There is nothing remarkable about the left one, other than the fact that it was found in an old house west of Sofia, Bulgaria. I usually do not believe such stories, but it was a gift from a friend, and I do not think he is making anything up - he has no reason to. One can only speculate on how it got there. I am guessing early 20th century?
The second one appears to be newer - my guess is mid 20th century. The hilt is bone, but what is more unusual is the scabbard. I have seen this type of stitching with little wire spirals on Ottoman pieces, such as kilidj scabbards. It tends to be on the back though, and here it is on the front of the scabbard. Why is that, did the stitcher make a mistake, or was it done so on purpose?
Also, am I right about my estimates on age and origin?
All comments are much appreciated, thank you.

Teodor