When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would try and locate the source of the squeak rather than just spraying silicone lubricant into the column head. For instance, if could be the lower column bearing, (way down under the brake booster). The noise could travel up the column and confuse you as to what is wrong. You may need to have someone else rock the steering wheel back and forth and listen to various parts of the steering column and even the steering gear with a long screwdriver or stethoscope.
You could even look for parts rubbing such as the lock plate cover, T&T extension, etc.
You can find quite a bit of information on disassembling and repairing the various C3 steering columns by going to http://www.corvettefaq.com and looking in the Steering section. There are several papers on the T&T as well as the standard (non-adjustable) columns.