Totally new poster here, so my apologies in advance to not being aware of the protocol in my thread.
I was given my grandmothers old Winchester .22 which I thought was a model 90 because the 'replacement'

barrel says Model 90 Long.
I brought it to the gunsmith to have it looked at and repaired for shooting, and he mentioned it might be a Model 6 with a Model 90 replacement barrel.
To me, after searching online, they look to be very similar rifles. Can anyone tell me if there are any key differences between the two models that I can use to help identify which one it is.
Here are some details:
My dad replaced the barrel many years (decade?) ago and had the stocks refinished. ......collector value I'm sure is near zero
There is no blueing on the reciever
The round replacement barrel is intensly blue and says Model 90 Long
I have easily fed in and shot .22 long rifles without any apparent damage or marking on the long rifle lead bullets
It doesn't feed in shells ~50% of the time and has trouble ejecting ~20%
THe serial number is 608643 (I think makes it ~1918 if model 90 or ~1923 if model 6). Both dates are plausible for the family history of ownership
No serial numbers on the barrel
No model number anywhere except the barrel
The gunsmith noted the forearm stock appeared to fit fine with the round barrel and noted this would be odd if it was fitted with an octagonal barrel of the model 90
Thanks