Gpm caster block fit on Ext flm a-arms on Stampede?

I'm suppose to be recieving my whole flm pede tommorrow and wanted to prepare. Will gpm caster block and steering block fit right on the ext. a-arm kit? I also ordered the caster block from here also. Will the gpm steering block fit on the flm caster block? I know for sure that the flm caster block will fit on the ext. a arms.

flm caster block + gpm steering block = direct fit on ext. a arms?

gpm caster block +gpm steering block = direct fit on ext. a arms?

I really really hope i dont Have to buy the nitro parts...i like 100 miles away from a hobby shop and dont want to have to order morrrreeeee stuff for this project. This project has been going on almost a month. My mamba max wants to ride this flm pede already!