When I was at the Missouri 154-Missouri 107 intersection in Monroe County in September 2012, a friendly crew of mowers waved and said hello and didn't give me funny looks even though I was photographing highway signs.
Note that both a rectangular "wide" marker is used for a three-digit route, as well as a square marker for the other three-digit route. Missouri appears to be making new signs of both types.
This intersection also marks the southern end of Missouri 107, which goes north over two arms of Mark Twain Lake to US 24 northeast of Stoutsville.