welcome to the forum.
we gotta know the chassis maker and size of your moho. ford is different than gm. the torques on the lug nuts also vary greatly. the torque on my lug nuts is 475 ft lbs. they do not come off easily. i hope you just lost a lug nut cover.
you should update your "signature profile" to include this info.
most rv dealers and truck stops have lug nuts and lug nut covers available in their parts departments.
01 WINNEBAGO 35U W20.8.1L SW Wa, Hi. Good Sam, SKP. AMSOIL fluids. BANKS ecm program. SCAN GAUGE II w/ Ally temp. 2 LIFELINE GPL-6CT AGM Batts on their sides. TST tptts. K&N panel air filter. AERO mufflers. TAYLOR plug wires. ULTRA POWER track bar. KONI fsd shocks, toad '14 smart car