Help - Bought for a £1

I bought this for a £1 on a car boot because I thought it was an usual set.
I’ve done lots of research, but have’nt really come up with anything.
It’s a cafe au lait set. Its stamped on the bottom ‘R’ ‘Reboucas’ 21 on each piece.

There is also an inscription on both pots.
Large pot - Amistonsa 1975

Smaller pot - Medalha Do Mes Abril 1975

I have no idea if they are silver or silver plate? how do i find out?

How much would this set be worth?

Thanks for all help.

no pictures again!