8 3/4 housing marking

A large X inside a circle, white paint. It's on the back of the center .68 a body. Thanks in advance.

What is the question?

What does the marking mean?

A mark that it was checked.

Does it have yellow markings that say A ?

Sometimes the yellow turns/looks white. The X might be an quickly written A that the bar in the A was missed.

Pics?

Here's some examples of originals:

I took these pics of an A body rear for sale at the Pomona swap meet in 2007. I think it was a 70-72 with bell drums. Vent location should narrow down year a little.

Looks like they missed circling the X on this one.

If you look closely at the circle there appears to be thicker yellow marking peeking through

What is best used to recreate these markings

Here's photos of my '69 A body 8-3/4 with a yellow "A" and an "X" circled.

The "A" was made with yellow paint, possibly enamel. The color is like school bus yellow, not lemon or pastel yellow.

The "X" and circle were made with a Markal Paintstik 80220, 80820, or equal. See here. These are under $3 at welding supply stores or click the 'where to buy' button.