Yes, it is too much....but that is the MINIMUM asking price now for an all-matching No4Mk1*. If you don't want to pay $400, you won't go home with the rifle, because somebody else
will pay $400.
Just a word of caution...there are some very industrious people out there who are jumping on this latest Lee-Enfield sales bonanza, offering parts-bin rifles that have been tarted up to look better than they are. If buying on the 'net, be sure to ask the right questions, even if they have a trader rating higher than Roberto Luongo.