Good call on the 83 series I like that even more than the Master or American choices. I think he could probably order many from Amazon zero bitted and then pin them up as needed. Also the 83 series has such a wide variety of body types. Good. Call.
Abus 83CS/45-300 S2 Rekeyable Schlage Solid Brass Closed Shackle 45mm Body 1 Inch Shackle Padlock Zero-Bitted https://www.amazon.ca/dp/B009S5Y694/ref=cm_sw_r_cp_api_mTsYzbAHMSPND
Check out the Abus 83 series padlocks. There are several sizes and you can put almost any core you want in them... They typically come with Schlage cores (from amazon) but you can replace them or get others as well. Here is an example: Click Me.
I used the LAB pinning kit and key decoder to pin up a similar ABUS SFIC for my brother. The pin kit isn't cheap, but it's mostly a one-time expense.