Timing of H4 dependants going to US

I’m in the process of getting my H1b petition approved by my employer. My question is that if I apply for my spouse and child’s H4 right now and take them along for the interview, can they come to the US at a later date, say after 4 months? I will be going as soon as I get the h1b.

Yes. If granted a visa , they can travel to US even later within the validity of visa