I am not sure if this of any major concern and I should've mentioned it a long time ago but...
Kathy made her gloves and prepared the lambskin for the vest and cummerbund a while back. She did a little research and talked to a lady who makes leather pants and other various leather garments. She gave us some info to prep the leather to keep it from stretching once you start sewing and wearing it:
* Wash the leather in the washing machine on cold with Fels-naptha laundry bar soap. You will need to use a cheese grater to grind the soap and mix it in a bowl of hot water then put it in the washer. I found it at King soopers in the laundry soap section. It is supposed to help clean the oils off, prepping for dyes and also just to clean it. Then take the leather straight out of the washer and stretch / staple it to a piece of plywood and let it dry stretched. Again, this well help keep the vest from stretching during sewing and when you start wearing it.....since there is a bunch of stuff hanging on it 
It seemed to really help with making the gloves.
