Yes the brochure is well known, in its 2 versions (English and German) - if I remember well it has even been uploaded in the download section of this forum.
It's an excellent document. However one must be aware that it appears that apparently not all of these models entered in series production or in service.
On the export market, the 12.5kg bomb seems to have been the most successful model. In 1940-1 such bombs were part of the arsenal of the airforces of Denmark and Lithuania (possibly other countries also, but only for these two there is a definitive identification)
This is a picture of the full range of Tolfvan production in 1938 - corresponding the brochure:
View attachment 203968
And thus is a picture compiling all the drawings of the bombs in the 1938 Tolfvan Brochure:
View attachment 203969
To come back to your find, note a small correction for the photograph that I posted: it is the Tolfvan 2kg (not 3 kg) M30 incendiary Elektron bomb.
The Tolfvan 3kg M30 fragmentation bomb had a similar fin and a surviving sample has been recently offerrd for sale in a Finnish auction site:
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