COLONIAL MEDAL : COLLECTING WW2 ISSUES ( NON-VICHY )

[numis]

As a collector of all the awards of all of the Allied Countries of WW2 I would like to include the Colonial Medal with relevant bars / clasps to my collection .

I would like to have specimens that were actually awarded / issued to recipients and not later restrikes .

Can anyone provide suggestions  on what to look out for and what to avoid 

A first and basic question is as to whether contemporary Colonial Medals and bars ( for WW2 non-Vichy  services ) should be in silver or not .

I have just seen a large offering which includes many medals and bars ( relating to WW2 )  in base metal , sometimes with a mixture on the same medal ( ie medal in silver and bar not ; or vice versa )