'86 B2000 Manual Tranny starts in gear

My son's truck starts while in gear with the clutch pedal not depressed.I have replaced the Neutral Safety Switch, checked the Clutch Position Switch. The Neutral Safety Switch I removed and the clutch switch both appear good by multimeter as does the clutch switch. Any ideas what else to check? My repair manual doesn't have a decent schematic, so I don't know where else to look.

"My son's truck starts while in gear with the clutch pedal not depressed" Do you men that it CAN start without pressing the clutch pedal down ? Because I think that government-mandated safety improvement did not happen until future models. For example, my old VWs can start in any gear, and without pressing the clutch pedal down.

"I have replaced the Neutral Safety Switch, checked the Clutch Position Switch. The Neutral Safety Switch I removed and the clutch switch both appear good by multimeter as does the clutch switch." This really confuses me, as a manual transmission truck would not have a Neutral Safety Switch at all; and are you sure that other switch isn't like a cruise control switch ?

It will start if it is in any gear without touching the clutch pedal.

Those are the names listed at Rock Auto and NAPA and such for those two switches.
The truck has never had cruise, so that isn't it. One site list the switch on the tranny as a starter interlock switch. but I compare that to potatos, potatoes....
If it isn't in neutral, or the clutch pushed in, it should start. They started putting them in in the 70s I believe, My 72 Pinto didn't have one, but they were fairly common around 76 from what I've found.

"It will start if it is in any gear without touching the clutch pedal."

Then that's normal for a 1986 B2000 (just like my old VWs). Is there a problem? Or is your son not as adaptable as folks used to be, to know to put into neutral before starting?