Postage Meter Stamps - Types And Catalog

Hello,

I have some postage meter stamps and know not much about them. So I have some questions, some general, and some about the stamps I have.

I found the online catalog here:
https://en.wikibooks.org/wiki/Unite...tamp_Catalog


1. Is this the best and most recent source for postage meter stamp types?

2. Some stamps show like a hardly visible overprint saying "METERED MAIL" in ovals, what is this overprint called, and is it relevant for finding a certain stamp type?

3. The GROUP D (squares) can have more than one "stamp" at the right, for example 2c and 3c, is there a listing for those combinations or are all just common?

4. Although I looked at the pages some time I still don't find all of my stamps. I am showing some of them here.

I think my stamps are all:
GROUP I
Sub-group IA

the red 1978 stamp and the blue 1979 stamp is
IA4.1. Models "RF, RT"

the two red 1979 stamps are
IA4.5. Model "RT-3"

the blue 1981 stamp is:
Sub-group ID
ID2. Models "5702, 5705, 5707"

the red 1947 stamp could be IA4.1. Models "RF, RT", "m" ?

Could all this be correct?

I was not sure about if the exact distance between the lines themselves and the two points of the colon is always relevant by Millimeters and if I have seen it correctly.



Thank you for all answers.

Hello,
As for question 1: Yes, it is the most recent and an ongoing project that's updated regularly. I haven't seen anything better or more comprehensive that covers the whole world.

2. It looks like a strong watermark on the paper.

Hopefully someone else can help with the other questions.

Thanks for posting. I did not know this reference was free online. I can only answer your question #1: YES (for US meters)

Thank you. About the watermark/overprint: I thought this has a term perhaps. You can see it in the 1947 stamp (what appears to be quite early for such a thing). Is this only related to the used paper, or does it change the stamp type? (I don't think so as I did not find it as parameter in the mentioned catalog)

For sure I would be happy to get some feedback about my try to define my stamp IDs.