I think oldsub is probably right. The truck was originally titled off of the original 216 motor which was the common practice in many states in the days before VINs. When the 216 was swapped out for the 235, the owners probably bought a blank ID plate and stamped the number from the title, otherwise there would have been no number anywhere on the truck that matched the title.
When the dreaded PO (previous owner) swapped out the engine he (or she) used the 216 cover to preserve the "original" look. This is a very easy swap that simply requires replacing two of the rocker arm hold down bolts with threaded studs (kits available from most of the vendors). You then have a 235 that looks, at first glance, to be the original 216.
