Can I replace a feeder afci breaker with a combination type breaker with out further modifications?

What are you calling a combination type breaker?

Don't know really, the old breaker says branch/feeder and the new one calls it a combination instead.

Most newer AFCI's are combination AFCI. Meaning they sense series and parallel arcs.
They are a direct replacement.

Why are you replacing it.

Going from 15 to 20 amp

What makes you think this is a good idea?
Unless all the wiring on the circuit is #12 (at the smallest) you cannot simply put in a larger breaker.

It is

Then why was it a 15A to begin with?
Sounds fishy to me.

All wires in the box 20Amp and below are the same gauge according to my micrometer. Only the 30 and 50amp circuits are wired with a larger gauge. Agree with you, not like a builder to throw away money like that.

Not really throw away money, but throw away 5A worth of circuit power. Why not just use 20A and be done with it.

The only explanation is in some places 15A circuits are required (Canada lighting circuits I think), and guys only want to stock one size wire for convenience purposes. IMO this is throwing away money.