FYI nobody is trying to knock your bike, it's a reference from a different for sale post of the exact same bike/color, just yours is much cheaper. This is actually a nice bike in a good price range in my opinion.
Here's the breakdown of what it's missing and what you'd have to pay for that part for it to be 100% original:
It has a later chain/spoke guard on it ($???)
MAYBE has the wrong freewheel ($???)
Has a later derailleur ($50-100)
Missing the pumpkin headlight ($3-400)
Wrong handlebar grips ($20-30)
GT is asking about the freewheel because it's very hard to tell from the pictures. If the chain/spoke guard and derailleur have been changed, it's very likely the freewheel has too. The correct freewheel and chain guard are pretty much unobtainium individually, a buyer needs to expect to buy another 5 speed to get those parts.
Good luck with sale!