If not, ask whether he is pleased with his mount. If viewing a mount in someone's home, be fair and note where the mount is hanging. If over a fireplace or in direct sunlight, any deterioration may not be the taxidermist's fault. In fact, ask the taxidermist for references several years old. This way it is possible to get an idea how his work will pass the test of time.
Terms are important as well.
Prices should reflect the taxidermist's talent and experience, and quality of the finished product. Don't pay more simply because the taxidermist thinks he is worth more, unless you agree and feel the work is worth the difference. Ask about delivery time. For the best taxidermists a year, perhaps sixteen months is normal. Some will quote slightly longer to allow time for unforeseen circumstances, but anything over a year and a half is unjustified, particularly if taxidermy is the man's full-time job.