Short trip. IMHO and experience a lot of weapons charges are "included offenses" - you bring yourself to the attention of law enforcement for some reason, good or bad, or no reason related to you[ i.e. your vehicle matches one wanted in connection with an offense].
In the course of that attention you will probably be asked to identify yourself, provide proof of registration/[insurance in some states] and told why you were stopped..officers may casually ask you if you have any weapons on your person or in your vehicle -i.e. do you have any submachine guns or hand grenades or other weapons? Regardless of your answer, unless you are being arrested, they often ask " May I search your car?" You may answer yes or not as is your right and they will not search your vehicle unless you are being arrested or they have probable cause such as a DRUG dog alert or seeing the loaded 30 rd PMAG on your back seat.
All that to say this, most LEO are not running around looking for weapons offenses on citizens minding their own business however IF they interact with you and discover a prohibited weapon you may go to the graybar hotel wearing their iron bracelets...i.e. DWI
while carrying a illegal weapon will probably get you charged with BOTH offenses while driving home from church with the same weapon would be A NON-EVENT, IMHO.
FWIW, I visited the Arch carrying my Endura Wave in 12/2009..the posted rule was NO knives 4" or more - mine was 3 13/16" and they did measure and hand back to me. Recently saw a post where that may have changed.
Glad your trip was a good one.