The Police Positive Special Mark V, was an updated PPS from Colt in 1994.
It was shipped with an underlug barrel that was more or less, a lengthened Detective Special barrel, and rubber grips.
It was rated for about 3000 rounds of +P ammo before it needed to be returned to the factory for inspection, and possible frame replacement.
The Colt line-up around this time was getting VERY confused. Models were introduced, discontinued, re-introduced, and discontinued again in rapid secession.
In 1994 the PPS Mark V was introduced. Next year in 1995 the PPS Mark V was "apparently" re-named just the PPS again, since that year Colt introduced their new stainless steel SF-VI revolver, to replace all the older "D" frame guns.
"Apparently" the PPS was discontinued by 1996, and "possibly" a VERY few 4" stainless steel SF-VI framed guns "MAY" have been made.
(You'll note all the apparently's, possibles and may's. Things were so confused, nobody seems to know for sure what was made and when.
In any event, production of the PPS Mark V would have been fairly low, since the lugged barrel PPS was only made for 2 or possibly 3 years in small quantities.
So, you have a probable collector's item.