There are many micronutrients to consider but those aside, 15-30-15 isn't too far from the amount of macros the average plant needs. Personally, I'd add more K and use at least one other fertilizer whose micros compliment the micos in your current fert. Different kinds of pot need different nutrients so no one can really say what ratio is best for a completely unknown strain.
you always want more K then N for flowering so i would get one with more K if you can find a 15-30-30 that will work but really any with more amount of K is good
Specifically to your question, yes it will work, that ratio is a basic flowering ratio (as opposed to a veg ratio). However, as these other blades have pointed out, there are other issues to consider.