NO. 3 - Prototypes (These are rare puppies)
38-55 wirh recapper on nose as well as the upper handle, as seen on eBay.
The "P" denotes the die being for a paper-patched bullet.  
Note the unusual open end.  Unknown if this is standard for all paper-patch dies as this is the first one seen.
There was some discussion as to whether these tools were really prototypes of the No. 3 and not the No. 6.  I
used to think the latter, but on further reflection, believe Doug Elliot's thesis that they are No. 3s is correct.  
The three I have seen have no patent dates, which even the earliest production tools had, and if they were just
early No. 6s, more of them should have been found.
Another very clean example, this one a 32-40 with a die for seating paper-patched bullets,
yet has a sizing station for grooved cast bullets.
                                                                                                                                                  Photos courtesy of E. Curtiss.
Note the "38" by the sizing station.  
First one I've seen with these markings.
This appears to be a factory modification of a single adjustable die to a double
adjustable.  Another first.
The die is marked "38" and the bullet-seating stem "R", for a round-nose Marlin
This version, a 38-55 M[arlin], has a sizing station with the pushrod missing.