The first number in a Philco model is year. These are 1938 radios. Models may or may not be similar. You can't tell by model numbers but rather by schematics available here on nostalgiaair.
Electrical parts, tubes, resistors, capacitors are interchangeable if they have similar values. New parts are available from AES, www.tubesandmore.com and others.
Norm
:I am a novice who is refurbishing a Philco 38-3. What are the differences between the 38-1, 2, 3, 4, etc. series and are parts and tubes interchangable with these models?