This message is already being advertised to all gun owners, under Project Prison Rape Exile.
2) What is to stop the next democrat from turning this on its head and using the registration against them?
Why, how could they? Gun registrations have never, ever, not once in the history of the Earth, let alone America, been used for confiscations. Except for California, New York, Cambodia, England, Soviet Union, Nazi Germany, Turkey, Rwanda ....
3) What is magic about 1968?
1968 is when the "Gun Control Act" was passed, which significantly changed the rules for gun ownership. Apparently they only want pre-those-rules guns to be registered. Note that the BATF was never granted to power to ban guns, only to collect taxes on them, by registration. But in 1986, they decided they wouldn't "accept" any more registrations, so all subsequent production of those guns became banned from private ownership - those are the Jackbooted Thug Law Enforcement Only firearms today.
Given the way they pick these dates and use these laws (It is ok to have acquired an automatic before 1968, but you can't own one made after 1986) it is oh so obvious that these laws are just stupid jokes whose only purpose is political.
I just don't have any faith in any politician any more. Every election is just pick your poison. Every last one of them is stupid, corrupt, and power-mad. And the agencies that they father are simply insane.
The ultimate demise of this republic is coming as plain as night and day.
Republicans are like the guy who wins the lottery, descends into debauchery and dissipation and squanders it in a year.
Democrats are the guy who wins the lottery and ODs before he even gets the first check.