Cook Islands Decimal Op Variety?

These stamps were together in an unlabelled envelope in a lot I purchased and, luckily, I took a second look before seperating the pairs.

Each pair seems to have one overprint in a heavy type and the other in a much finer type. As well, the 7 cent single which uses the finer type for its printing, has a period in front of the 7. I have no other stamps from this issue to compare them to and do not know which is more common, the heavy or the fine print.

And that is, by the way, one of the happiest looking fish that I have seen outside of a Disney movie!

Cook Islands seems to be one of those places which for years has produced copious quantities of stamps with miniature sheets, souvenir sheets, imperforates and suchlike but these are a little earlier in the scheme of things.

Are they legitimate rather than deliberately produced varieties and does any catalogue list them?

These area all from the 1963 set original SC#152 (6d.) 153 (8D.) and 154 (1sh)
They were reissued in 1967 with these surcharges when the currency changed.
Scott's indicates that two surcharge types were used on left and right with lighter and heavier type.
There's no mention of the decimal 7 in particular, but it does say "Numerous varieties of surcharge include wrong font 'c', thin numerals etc." I guess we could assume that etc. includes extra periods?

Also your new Scotts numbers for 1967 are SC#185,186 and 187 respectively.