Too close to call.
If we want some real stakes:
Mitch sells first = money from sale goes to Shawn.
Shawn buys first = guitar goes to Mitch
Or more realistic:
Mitch sells first = 25% of the money from sale goes to Shawn.
Shawn buys first = guitar goes to Mitch for 4 months (which is about how long he would keep it anyways...)
If we want some real stakes:
Mitch sells first = money from sale goes to Shawn.
Shawn buys first = guitar goes to Mitch
Or more realistic:
Mitch sells first = 25% of the money from sale goes to Shawn.
Shawn buys first = guitar goes to Mitch for 4 months (which is about how long he would keep it anyways...)