You're correct about the inverted matrix, however the stamped matrix on the original is 1C, on the reissue it is 2C, I have both in front of me as I write this.
I'm amazed it went to a second pressing in 1967 as it hardly sold anything.
The brown on the label is way lighter on the reissue incidentally.
* there may be a few anomilies with deram as I just sold an original Quik - Berts Apple Crumble, I know it's an original, it's got the proper stamper number, yet the small matrix on the label is the right way up, never seen one like this.