Here is what I have been able to figure out, the 1975 FM coin I didn't find in any worthwhile sharp image, so I have only compared the two slightly different types supplied by Frenchlover, although I substituted the right coin with the coin from my collection to get a HI-RES image.
Since I'm a pessimist, I believe my coin is the common coin minted in the US, but of course I might be wrong.
If we believe my coin is a common one and assign it to US year line, time will tell if I'm right, by the percentages showing up on the two year lines.
Today it seems people have been able to put most of the 1975 coins into the US year line. I put mine in there because of the chance 10:1!
Shall I make a CR with this as basis, or do you have other comments to be taken into consideration?
US Mints did not make any Philippine coins after the 1976 ones.
Note that the year is calendar year. Year 1976 if for coins with a 1975 date and year 1977 is for coins with a 1976 date. US Mint made no coins with a 1977 or 1978 date.