We used Out of Doors Mart to buy our outriggers. Their webpage has a nifty diagram of an Airstream frame and you click on the location of the outrigger you want to replace. As you pointed out, there are "shorties" for the front and rear of the trailer, there are left side and right side outriggers both forward and rearward of the wheel wells, and there are folding step outriggers. We ended up replacing 9 outriggers on my friend's Sovereign
I've used High Sky for some items too. They have a big inventory of vintage Airstream parts.
WBCCI #8607 VAC Region 11
KnowledgeBase trailer renovation threads: 69 Globetrotter, 76 Sovereign, 75 Overlander, 66 Trade Wind Such fun !