This is fine in this case. Vengeance has all of SMT5 plus its DLC included, along with the new content. There's no reason for the old one to stick around anymore, as it'd just confuse potential buyers. Plus, if you always have the old version and need to redownload it for some reason, you still can.
"Be good to yourself, because everyone else in the world is probably out to get you."
- Dr. Harleen Quinzel