generic drillable tank question

I know this has probably been beat to death, and I tried a search on the forums but came up with a lot of topics that didn’t fit what I wanted to know.

So here is my question:

Is it generally accepted that the larger tanks (75g and bigger) do not have tempered glass and are drillable? Or does it depend on the manufacturer or the age of the tank? I did a quick search on the interweb and found a few website forums that have said that anything 75g and larger typically do not have tempered glass and can be drilled, but I wanted to get the general consensus from this group.

I am looking for a tank that is 75g or larger and have found a couple of people now that have 75g tanks that are not reef ready, and I am wondering if I can drill the back glass, as opposed to having to use a hang on the back style overflow. Any help would be very appreciated.

ALOT are drill able and the bigger the tank the thicker glass is usually not tempered but you need to always look for the tag or contact the manufacture to be sure.
My new tank has 3/4 inch glass on the bottom and 1/2 side and I don’t believe any panels are tempered

Yea, that is my fear is that these tanks are both used and probably no longer have the tags or markings, and the owners may not know who made the tank or when it was manufactured to be able to contact them.

I should be able to use the cell phone and polarized eye glass trick to determine if it is tempered or not, but I wasn’t real sure if that was needed on the larger sized tanks.

I have not heard of too many tempered 75 gallon tanks. The tanks that are usually tempered are the 55g and tank / stand combo kits.