IIRC inverted flare uses straight threads.
I stopped buying pre-made pigtails. Whether they have a pipe thread or reverse flared end both ends of the hose use crimped fittings with barbs. I always had problems with propane leaks between the hose and the fitting. Especially when the hoses got stiff in the winter time and I was switching tanks. The hoses would always rotate a little on the barbs because they were so stiff. I now get my hoses made at a local industrial hose supplier. I took the reverse flare fittings out of the regulator and put in pipe threaded by 45 degree flared elbows and bought green acme nut fittings with male pipe threads on them.
The hoses I have made have a female 45 degree flared swivel on one end and a female pipe thread on the other end. Although they have the same internal diameter, the hoses are a little fatter and the crips are a lot tighter. No more leaks or hoses rotating on the crimped hose barb's.