WTK Why is this a Post-86 and not Pre- Uzi?

[Nitzel]

Check this out: http://www.gunbroker.com/item/604082720

Springfield import IMI Uzi, Israeli receiver markings, imported 1978 according to ad. So why would this not be a pre-86 sample rather than post-86? Reweld maybe? Other ideas?

Curious, trying to understand....

Thanks

Update: OK DISREGARD. Seller advised mfg'ed in 1978, imported in 1990.....