Cook Islands - Rarotonga Overprint

Hi,

I am wondering if you can tell me about this stamp.



It has a Cook Islands overprint on the New Zealand KGV stam, but the overprint is somewhat different from what I see in my catalog.

Also, it appears to have been used for postage in New Zealand. Were postage stamps of the Cook Islands and New Zealand interchangable?

Thanks.

It appears to be SG57, from June, 1919. This overprint is on a typographed stamp, while most of the values in the set were on engraved stamps. This is on chalk-surfaced paper, and most of the set is on Cowan unsurfaced paper. Yours should perf 14x15, while most in the set perf 14x13.5. The values differ in each overprint.

So, depending on the stamp illustrated in the catalogue you are consulting, there could be numerous variations.