Sorry. Just saw your posting.
When you say "replacement" do you mean a place to buy those particular parts, exactly as specified?
Or are you looking to replace the "type" resistor they are?
(I wouldn't know why but thought I would ask.)
I use Antique Electronic Supply for most of my discrete components:
https://www.tubesandmore.com/products/resistors2.7K 1/2W MF 1% = R-M2D7K
300 ohm WW 5W 5% = R-Q300
If you use their value select dropdown on each type you should be able to find these part numbers.
Not expensive at all. You can of course spend a ton more but for this kit I think these prices are about right.
You can also try Mouser but I try to support the shops that cater to the tube DIY crowd. :)