Stromburg carburetter cover screw

My 1970 E with 2 Stromburg 175 CD2 carbs, there are four screws hold the cover on.
Three are the same, but one is longer with a hole in the bottom. Both carbs had this one hole-in- longer screw, same location on both. Is there a purpose for this screw, like being a spare for somewhere else in the carb? It seems to have no purpose where it is, other than holding down the carb cover.

I can only think it’s for a little metal tab under the screw that identifies the carb type. Although it’s wafer thin often engineering design make provision to box tick.

I believe it’s for a lead anti-tamper seal. See this thread, and in particular, post #3 -

Makes more sense now, either a place to hang a tag to identify the carb,
or a tampered with seal (if broken) for the cover. Reason for my asking about the screws is that I was replacing the screws with new SS screws, but wondering if the old soft-metal screws expand or function better with increasing temperature? Doing more harm than good in swapping them out with stainless?

Swapped all the exterior screws on my S.U.s for stainless. Use a bit of aluminum based anti seize on the threads. I remove the vacuum chambers every year for a clean and polish. 18 years later still looking and working fine.

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Thanks Steve. The new SS screws do look better than the buggered-up Phillips heads on the old screws.

The reason they are “buggered-up” is because they are not Phillips heads - they are Pozidriv. Note the etched lines between the arms of the cross.