Chasing Malta (Again): 1976FM Matte 25 Cents Graded

Well, quite a few years ago I found in Malta a likely very rare 1976 matte unc. 50 cents, but also a 25 cents. I had the 50c graded at PCGS and it came back "64" and finally submitted the 25c that came back "cleaned" - with all due respect it absolutely was NOT and I had posted it. Some while later I got a second 1976FM matte 25c and had it graded at NGC, and lo and behold, came back with a "64" also. To date, these three are the only three mattes that I have seen on the market and had recorded original mintages of 150 for the 50c and 300 for the 25c.
The best I can gather, these were struck and then sent off to Valetta and never handled in any special way. They were of similar/same design to the Royal Mint struck coins and likely blended in locally & never identified as anything special. I can only imagine and anecdotal experience tend to support that they are very rare; however, no real demand so that when found or if found not generally expensive. I would submit that the leftover Krause and derived Numista and NGC value guides have them valued very low.
My suggestion is that they just leave a blank to value as they really don't have an established value.
Anyway, here are the pictures of the just-graded NGC 25c: