You should carry as comprehensive a stock of locks as space and cash flow permits. the following would be the minimum required.
all of these items available here

2 - 2.5" 3 lever dead locks

2 - 2.5" 3 lever sash locks

2 - 3" 3 lever dead locks

2 - 3" 3 lever sash locks

2 - 2.5" 5 lever dead locks

2 - 2.5" 5 lever sash locks

2 - 3" 5 lever dead locks

2 - 3" 5 lever sash locks

2 - 2.5" 5 lever B.S.dead locks

2 - 2.5" 5 lever B.S.sash locks

2 - 3" 5 lever B.S.dead locks

2 - 3" 5 lever B.S.sash locks

5 cheap rim cylinders

a selection of euro profile cylinders

30/30

35/55

45/45

40/60

1 oval profile cylinder

hasp & staple and some padlocks

"If you don't have it in your van you can not sell it"