Is there difference between Philippines BU and Matte sets? Do Matte sets exist?

Hello!

Does anyone know if there is an actual difference between BU and Matte sets?

According to SCWC 2 sets were issued:

One is a Specimen set (MS6; 3850) and another enclosed in Franklin Mint folder (MS5; 5877).

This website also lists these sets (but also a different one, packed by the Central Bank):

https://www.numismatics.ph/coins/coin-set/1975.html

They list: Matte set (FM): 3850; and a BU set (FM): 5877.

So far, from mintages we can conclude that Matte set is Specimen set (MS6); and FM folder is the BU set (MS5).

However, the website provides pictures only to BU set, where you can see “BU specimen set” (MS6; 3850) written on it.

https://en.numista.com/catalogue/set.php?id=3809 Same on Numista.

I suppose that the set on Numista should be “BU/FM holder” set (MS5, 5877). The coins in it also don't look Matte.

But this leaves a question: What is the “Matte/Specimen” set? I tried to find pictures of it on the internet, but I wasn't able to.

My guess is that they were probably packaged in the same holders and only differ in quality of coins. (Or maybe Matte were issued individually or without packaging?). I did not find any proof of either.

Does anyone know any information about them?

And the same question about these year BU and Matte set:

1976:

https://www.numismatics.ph/coins/coin-set/1976.html

1977:

https://www.numismatics.ph/coins/coin-set/1977.html

I wasn't able to find pictures of 1977 non-proof set, which would make sense if only 354 were issued. But according to SCWC and the website 10 000 Matte sets were issued, which I also didn't find pictures of. Something doesn't add up.

FM Matte coins after 1974 were usually sent to the country's central bank to do with as they pleased. They were sometimes assembled into sets locally and sometimes just dumped into circulation.

Then it makes sense why the 1975 uncirculated set (assembled by the central bank) has mixed normal and Matte coins. And also why there are no Matte sets, because it seems they didn't produce any sets with them. The only question remains, why did SCWC list them as sets?