Regarding the Soviet passport:
A series of Soviet passports of the sample of 1974 consists of Roman numerals (from I to XXXIII) and two uppercase letters. The numbers reflect the sequence of issuing passports. The letters are the region code. Each region has its own code. In Moscow for example is MJ and SB, in the Krasnodar region — AG and TM, in the Kirov region — IR, etc. This does not mean that Muscovites can not be Kirov passports and Vice versa (it is necessary to take into account the migration factor), but if in Moscow the signature sheets go entirely Kirov Krasnodar or series, it should alert the controller.
All rooms of passports of the USSR are in the range of numbers 500 000-750 000. If You get a passport with other rooms — it's either a typo or an outright fake. Stitching is rejected in any case and petitions the collector subject to partial inspection.