Portugal 500 Escudos Vasco da Gama Bridge

Dear all, 

is there a simple way to distinguish between 
500 Escudos (Vasco da Gama Bridge) 1998 
Circulating commemorative coin: System 1981-2001 – Opening of the Vasco da Gama Bridge 
Silver (.500) • 14 g • ⌀ 30 mm KM# 705, Gomes# R 147.01, N# 13044

and

500 Escudos (Vasco da Gama Bridge; Proof issue) 1998 
Non-circulating coin: System 1981-2001 – Opening of the Vasco da Gama Bridge 
Silver (.925) • 14 g • ⌀ 30 mm KM# 705a, Gomes# R 147.02, N# 79620

Thanks!

Sincerely,
Chaosharvard

One is proof, the other not

I know, but if - for whatever reason - a coin was removed from the box, the "proofness" becomes less obvious. 

Density measurement (doable but subject to error) or magnetic slide (very easy) will distinguish them.

See here for density discussion.  https://en.numista.com/forum/topic109244.html

See here for magnetic slide discussion:  https://en.numista.com/forum/topic128773.html#p1042674 and this screenshot of different silver content coins:

Or, save yourself a lot of time and trouble and take them to a jeweler or coin store for XRF testing.