Sweden 1.40kr Fluorescent Paper - Interesting Letter

Hi Everyone -

For all the Sweden experts out there -

I received this stamp in a collection a couple of years ago, and decided to finally throw this out on the internet and see if it's something of note or not. The letter states that this is one of 400 338y 1.40 KR stamps that were part of of 4 rolls total, 100 each, in mint condition. I don't have access to the catalogs referred to, are these stamps actually a thing or is this some snake-oil? Apparently the owner of this stamp paid $1450 back in 1980 for it. I'm including pics of the stamp (on the left in glassine) and the original letter, as well as ChatGPTs translation of the letter here.

To:
Mr. Karl Ernst
Belschnerstr. 13
7140 Ludwigsburg

Subject: Your mint Sweden collection

Dear Mr. Ernst,

In the shipment of February–March 1979, I supplied subscribers to my Sweden mint stamp service with stamp No. 338y, together with the following explanation:

Definitive stamp, 1.40 kronor, issued in 1968 on fluorescent paper.

The normal version of this stamp was sold at post office counters from 1948 to 1973, a period of no less than 25 years.

Up to the present time, only a very small number of this definitive stamp printed on phosphorescent paper have been found in Sweden, and these have all been used (cancelled) copies.

The exact number printed of this very rare stamp is unknown, as it was almost certainly produced as a paper-related error. It is certain, however, that this stamp is extremely rare, because no mint (unused) example has yet been discovered.

The difference from the normal issue can easily be seen under any ultraviolet lamp (yellow phosphorescence).

In the Europa-West Catalogue this stamp is listed as No. 338y, fluorescent paper, with a catalogue value of DM 50.00.

Through my good contacts in Sweden, I succeeded in obtaining a small quantity of this very rare stamp for my subscribers.

Since no mint example is known to exist, subscribers to the Sweden mint collection received a cancelled example instead.

For easier identification, the stamp is additionally marked on the reverse with "Y."

At that time, the cancelled stamp was supplied for DM 43.50. Today—after scarcely more than a year—it is already valued at DM 80.00.

As my Swedish source has informed me, a total of 4 rolls of 100 stamps each—that is, 400 examples—of this rare variety have now been found in mint condition.

He has succeeded in acquiring one such roll (100 stamps) for the customers of my company.

Today you are receiving from me one mint copy of stamp No. 338y for your collection—one of only 400 examples currently known.

This stamp is currently listed in the catalog with a net value of DM 1,800.00. My price to you is considerably lower, namely:

DM 1,450.00

When one considers that this stamp owes its existence not to speculation but rather that it is a genuinely important and authentic rarity—as only rarely occurs—I believe you will agree that this is a favorable buying opportunity.

If you decide not to purchase the stamp, please return it to me today by registered mail. Hundreds of subscribers to my Sweden service are waiting for the opportunity to receive such a stamp.

With kind regards,

(Signature)
Erika Scheller

And sorry for the correction, prices are in DM and not dollars, so my original post was wrong. With DM values at the time in 1980, they paid ~$819 for this stamp.

You should check the fluorescence. The paper should glow yellow under ultraviolet light. If genuine, it's certainly uncommon. The 2025 FACIT catalogue price (in Swedish currency) is 3500Kr mint and 180Kr used, which is about $360 and $20 US. Either prices in general have fallen since your letter was written, or some more have been discovered.