Yugoslavia 1939 Issue "Ships":

And another one to show - and it is with engraver's mark "S".

Scott catalog have it under number B90/93 with high catalog value of 190.00 US$, and Michel catalog number is 385/88 I with much higher catalog value for full set of four - 600.00 euro.

Most of sets available are with some kind of paper fault, or gum problems, and certificate is preferable!

From my experience, set in perfect condition is almost non available, and full set with certificate for each stamps I didn't "meet" for more than 30 years - so, keep an eye on this set!

MILCO --- I don't see the engravers "S" on your stamps . Can you enlarge one of your stamps .

Those stamps with the "extra " S is a highly specialized printing , sounds like most Yugo collectors would have no interest in high price special printings . The problem is finding a buyer for the set .

Floortrader:
I try to enlarge it, but it is "lost in process", because of resolution.
Really don't have big experience with this kind of work.

But "S" mark are there where arrow point it.
Than, it is not special printing, it is engraver mark put on one position in printing sheet, so the quantity available is very low.

When talking about catalog price vs market price, You are correct that this kind of material is not for "standard collection", it is for people that specialized in Yugoslavia material/collection.
I personally, have an "reference" collection, and this kind of material (engraver mark, perforation variety, fluorescent paper, errors) must be there, but other and most of collectors will be just fine with "simple" issues and fill the space in album with it.

And what I see from other collectors, that they have in albums used and mint material in one set, just to fill blank space, by my opinion, it is just wrong way to do it, take or mint or used complete set to the album!
I have experience over 35 years, and when someone come, with album, in mixed condition, You will not find expensive samples there, and mix condition of set (used and mint) just put on offer to the "sad" level.

To find someone who is willing to buy this kind of material is not big problem, because on this small planet we have few hundred collectors that specialize in Yugoslavia material, and they are very specific in need, insisting on quality, certificate and so on.

Yes, I'm not putting my 1c magenta in my Commonwealth album. Holding out for a mint copy.

GeoffHa:

Do as You wish, but when I see set with catalog value of 600.00 euro/$, in mixed condition, half used CTO and half mint, and seller want for this "expensive" set money according catalog value and when person hear, that this kind of material have just 0.05 US$ per stamp, if he will find someone willing to buy it, than You can imagine which kind of "face" seller have, and it is sad side of realty in collection that are in mixed quality of material.
Yeah, we are not talking about single stamp, but for set/s in collection.