just to clarify, that means my system can handle 4000mhz right?
Yes, it should providing it's good RAM. (Preferably with Samsung b-die chips).
"(OC)" in 5100(OC)/ 5000(OC)/ 4866(OC)/ 4800(OC)/ 4600(OC)/ 4533(OC)/ 4400(OC)/ 4300(OC)/ 4266(OC)/ 4200(OC)/ 4133(OC)/ 4000(OC)/ 3866(OC)/ 3733(OC)/ 3600(OC)/ 3466(OC)/ 3400(OC)/ 3333(OC)/ 3300(OC)
refers to IMC (Internal Memory Controller) located in the processor. in your case 3200MHz and it's considered an overclock if memory has to run at higher frequency.
*Note: RAM frequency and speed are not same thing. "Speed " is actually performance that's influenced by frequency, latency etc.
Speaking of performance, Ryzen is still "happiest" with 3600MHz RAM with as low Cas latency (Cl16 or less) as possible, above that gains are quickly diminishing unless you need and use software that is greatly dependent on memory speed.
So, for best performance/price ratio, I'd suggest you get 3600MHZ RAM from from QVL that has lowest Cl at 3600MHz. and use XMP to set it.