You can also check with Army/Navy stores or if near a post, check with the Defense Reutilization Mananagement Office (DRMO) as the up rights that were issued with the General purpose tents (GP Small, GP Med) are almost identical to those i have seen called for in the regs, save for galvanized end caps and pins. You can of course cut them down if they are a bit to tall, but they work great.. and look alot better than 2x2s or 2x4s.
And here is a thread on this issue..
Co A, 2nd Battalion Ga Sharpshooters/64th Illinois Vol Infantry "Yates' Sharpshooters"
Savannah Republican Blues
Co C, 3rd US Infantry
Ships of the Sea Maritime Museum & William Scarbrough House, Savannah, GA
"I hope to live long enough to see my surviving comrades march side by side with the Union veterans along Pennsylvania Avenue, and then I will die happy." - James Longstreet at a Memorial Day Parade in 1902.