Few Romanian Stamps From Collection

Hello. I have two questions regarding these stamps. They seem to be mint but are cancelled. The marks appear to be very precise, does that mean they are meant for collectors? Secondly, the top two rows have the same stamps but in two different sizes. Was that common?

Cancelled to order, then sold to the international stamp trade. Using the same design in a smaller or larger format isn't very unusual.

Thank you.

GDR "buildings" set (from 1973 to 1981),mostly CTO

This is the "Transport and Communications" set, of 1967-1968
22 stamps in the definitive set.
Yes, some stamps same design, differing sizes. (You will have to use a catalogue, to establish the 2 releases later in 1969 and 1971 )

As advised yours are CTO = Cancelled to order, for collectors to secure much needed overseas currency.

Some of these CTO stamps, have mucilage that defies any sort of removal, I believe it to be animal based glue. One of the very few stamps I have ever thrown out.
Romania is a fabulous challenge for collectors. Requires about 5-7 albums.

Pages correlate to Steiner 1967 Page 17

Well that was a blast from the past!