Small – but interesting – differences can be found in the Rolex Cal. 618 / Type 2 movements used in vintage Ref. 6152 Panerai watches: the bridges received different engravings, being technically the same (15 Rubis, no incabloc shock protection). Note the different position of ROLEX and 15 RUBIS!

For a better understanding, the differences are colored:
Rolex Cal. 618 / Type 2 = pink
Rolex Cal. 618 / Type 2 mod. = yellow.

Such differences in engraving the bridges are similar to the Rolex Cal. 618 / Type 1 and Type 1 mod. movements, which were used in Ref. 3646 Panerai watches. We have published these differences in our 2nd book “Vintage Panerai – The References”, in the chronological classification (page 12-29), and also illustrated in chapter I.VII (page 149).

Referring to our earlier posting about the different Rolex movements in vintage Panerai watches, the characteristic features of the Type 2 movement (used in Ref. 6152 watches) are:

15 Rubis, no Incabloc shock protection
(balance cock engraved with a “plus-minus scale”)
16 Lines, power reserve approx. 36 hours.
18.000 half-oscillations per hour.

As just recently another rare Ref. 6152 watch surfaced, we know that there exist different engravings on the bridges. In the graphic here you can see the first discovered version with “ROLEX” and “15 RUBIS” engraved on the center bridge (see chapter II, page 180 in our book “Vintage Panerai – The References”). The other today known engraving version is shown here (Beside the differences in the engravings, the characteristic features of both movements are the same).

You can read and see more about the different versions of Rolex Cal. 618 movements in Panerai watches in our 2nd book “Vintage Panerai – The References”.