The gem or bar is not how you tell the age of a Castello. That usually indicates which market it was intended to be sold in. Castello will still, occasionally, use the gem in order to preserve that as a trademark.
To find the date of a Castello, check to see if the Castle stamp has a number inside it. If it does, add that number to 1947. For example, if you see a 76 inside the castle you'd know that the pipe was made this year (1947 + 76 = 2023).
If it doesn't have a number, it was likely pre-1987. Closer pictures of the nomenclature would help us give a more accurate dating.