Catalog Number ID Request

Hello! I'm a US collector, so I'm out of my depth with this item that was mixed in with a bunch of US covers. I'd be grateful to get information on why this item has two imprints (was the green 1c printed after the fact, like a surcharge?) and also, if you would, the catalog number. Cheers!

Scroll to the last item

https://www.stevedrewett.com/index....y=&sotmp=no&

Thank you very much NSK!

Here is a scan from the Unitrade Specialized Catalogue, 2018, which identifies it as "U41a".

Thank you stamporator. Ah, multilple catalogs. Wasn't aware of the Higgins and Gage catalog (from the listing NSK provided). I looked up the Unitrade catalog and on the cover it says that it uses Scott numbers. How is that catalog different from a Scott Canadian catalog? Cheers!

Just to confuse matters even more, Canadian postal stationery has its own catalogue by Webb. Unfortunately they changed all of their numbering in the latest version and Unitrade stopped cataloguing Canadian Postal stationery when Webb issued that version. I do not know of any Scott listing of Canadian Postal stationery.

So right now you need to be very careful when buying Canadian Postal Stationery because it may have a Unitrade number (Based on Scott numbering format); a Webb edition 7 with its own numbering; and a Webb edition 8 with total new numbering.

Greetings. I have looked up in Webb's catalogue, 8th edition, and this item is catalogued as #EN803. It is listed as "The 1935 Compound Die Issue." Based on the catalogue price, it would likely be a common type of preprinted envelope.

Thanks for your replies and the additional information. I had a feeling it might be a common item, but I like it anyway. :)