That sounds rather high for a boat of that size, and looking at the way it's sitting on the trailer I'd expect it to be much less than that. I have a 23 footer and can easily lift the tongue up, though admittedly mine should have more tongue weight than it does.
Actually, I'd consider 450# approaching dangerously light for a 4850# trailer. It should be 10-15% of the total trailer weight. Too light, and the trailer is prone to sway.
I don't believe Tesla publishes a tongue-weight limit, but remember that the tongue weight you do have comes out of the GVWR as payload (on any car).