Yep, as Jarl points to, it's a dial for a Carrera 30 (hence the 30 minute capacity of the register). The Carrera 30s replaced the Carrera 45s for a couple of years at the end of production of the first series of Carreras, being sold alongside the existing Carrera 12s.

The Valjoux 7730 is a (very) light reworking of the Venus 188, Valjoux having bought out Venus in around 1967. The 7730 movement is a bit wider than the Valjoux 72 and 92 that had been used for the Carrera 45s and 12s but it is almost exactly the same width as the Landeron 189 that was used in the Dato 45s and doesn't have the extra depth that the L189 does that necessitated changes to the caseback to fit. So your dial should fit in a regular production run Carrera case (the later the better).

Some measurements in more detail for those who like this kind of thing!:

Valjoux 7730 diameter 31.05mm, height 6mm
Valjoux 72 diameter 29.5mm, height 6.25mm
Valjoux 92 diameter 29.5mm, height 6mm
Landeron 189 diameter 31mm, height 6.85mm

The valjoux 72c/723 used in the Carrera 12 Dato is deeper again at 6.95mm, which goes some way to explaining why we see these in a couple of unique cases rather than just reusing the standard Carrera case.

Valjoux soon improved the 7730 to produce the 7733 (two register, no date), 7734 (two register with date) and 7736 (three register) that we see in manual Heuers throughout much of the 70s. The 7733 shared its dimensions with the 7730 but the 7734 was deeper at 6.7mm and the 7736 deeper yet at 7.4mm - by this time, though, Heuer was using cases deep enough to house the 7.7mm height of the Calibre 11/12 so the extra height of the newer manuals over the 7730 didn't cause any problems.