The finished motor sure looks good. The only nits I can find to pick are that there should be an additional plastic piece to organize the plug wires. It is held by the wires themselves, and it goes between the rocker arm cover and distributor. Also, it is difficult to see the metal line from the fuel filter to the carb.
In another post you indicated that you would change the fuel pump, but it looks right the way it is.
From the Lincoln parts book, the front cover is also listed as B9SZ-6019-A for the 58-9 Lincoln. (My book is 56-59). The oil fill tube for 58 is EDF-6754-A, and for 58-9 is listed PB8M-6754-A with the note: Use with PB8M-6750-A indicator when replacing EDF 6754-A on early 1958 Models. The 59 Models use the PB9M-6750-B indicator.
Yes, many of the Lincoln parts dealers have the 430 items, but they are way more expensive than the Tbird guys.