Thank you all for your responses and insight.
First, original specs were based on prior successes in nearby communities where 4' x 8' hand carved Welcome signs were installed. That set a baseline for comparison. Specs are not absolute, but if changed, the change cannot be so much to skew the comparison.
Since the proposal request is from a government purchase from public funds, the government is required to seek proposals from qualified sign makers and cannot simply pick their favorite sign making artist if that supplier is not the "best" overall, considering all factors. Although not based on price alone, price is significant where there are multiple qualified suppliers. Here, quality of sign appearance and longevity of retaining that quality are also important.
When one of the sign makers quotes signs made from Komacel with machine routed lettering, instead of HDU that is hand carved, comparison could be skewed. Since this is a competitive process, it makes sense to gain neutral opinions from professionals who do not have a possible self interest.
The location at issue is in the center of the eastern end of Nassau County, Long Island. When looking on a map that is probably at about the 75% mark on the western end of all of LI. The potential bidders are all qualified veteran sign makers.
Based on your comments, it appears that there is not a clear selection between the two options, so price may end up to be the determining factor.
Thank you again.
Tom