Heuer ref 13-1

hi all. I have just bought this heuer ref 13-1. It’s keeping perfect time and chronograph functions are working perfectly. The PVD has worn a bit and crystal has seen better days. Im very new to heuer watches but have noticed the date subdial is plain grey and I’ve only seen with white markers and never plain. The crown is unsigned. The one thing I have noticed is on the photo from the heuer catalogue the heuer shield seems to be very low and near the white marker at 6 o’clock but on others I have seen the heuer shield is slightly higher. I really don’t know if the one I have bought is genuine. It feels genuine and I like it but who knows?.Could I have people’s opinions please

I’ve seen a few over the years that don’t have the white indices around in the date “subdial”, no idea why some do and some don’t but certainly don’t think it’s abnormal.

I mentioned also about the Heuer shield position and size also not being an issue in my eyes.