Is this calcium deficiency?

No 😇

No, not calcium deficiency, but burning from over feeding. There is nothing you can do at this late stage to "fix" anything before harvest time.

You have a little nute burn. So your spotting could be a lack of the mineral calcium, but if you’re already feeding calcium it is more likely the mineral could be locked out from incorrect ph or high PK dose locking out the uptake of calcium. Best of luck with your grow.