Smiling Larry has previously been recruited and assigned to the weapon shot when I ran into him a second time at a random encounter location. -He was still being counted as a settler at the location I sent him to. -His dialog had no option to recruit him a second time. -His inventory and caps were the same as if he were at the weapons shop. -The Weapons shop was still assigned to him even though he was no longer at the settlement.
Since he is one of my main sources of ammo I reloaded a previous save. I do not know if he would eventually find his way back to the settlement he was assigned to or not.