Help With Belgium Specialized Catalogue Value For These Stamps

Hello, I recently acquired several pages of Belgian stamps. Among them are a bunch of booklet stamps and pieces. I have found most in my Michel catalogue but there are a few thtat are not listed in my catalogues, The stamps in question are 1.50F King Baudouin with attached "Use Postal Code: labels. On collector network web site these are listed as 1561j - 1561o which I assume are references from a Belgium Specialized catalogue. I am seeking catalogue values for used copies of these items.

this is the 1561J acoording to the OBP.(Belgium specialized catalogue). subnumber PU202. Catalogue value used/unused is low. about 0.70 dollar, retail value is therefore also low.

Thanks for that Johan. Are all of these 1561j - 1561o the same catalogue value?

yes, all have the same catalogue value.