While I think it's a "know the culture" situation in attire, a visitation isn't a funeral. If I didn't have time/place to change, I would wear my work clothes to the visitation, but I would dress in the a.m. if I knew I would be going to a funeral.
Story time: When I worked at Evil Oil Company, one of my co-workers committed suicide. In the chaos of dealing with police, HR, etc., no one thought to order the flowers for the funeral in time for delivery to the church. It fell to me to drive a company van, pick up the wreath, and take it to the church. I wasn't planning on attending the funeral myself, as I didn't know him very well, so dressed for a normal day of moving file boxes. Someone discovered that I was doing the flower delivery and people started asking me to drive them. Once there, these people had no way to get back, so I had every intention of waiting in the van until the service was concluded. This "wasn't acceptable" so, yes, I attended a full-on Funeral Mass in blue jeans and a work shirt.