It's very obvious that the motorcycle rider portraying Snake when the bike is actually being ridden is not Rob Reiner.
When Laurie is telling Shirley that she shouldn't judge Snake by his appearance, she uses the example of having been uninvited to a boy's birthday party when she was 8 because she got braces. But in Season 1 ("Old Scrapmouth"), Laurie was devastated by having to get braces at 16, as though she'd never had them before.