Hyundai is the leader in the ship building industry, isn't it???
Look, resistors from Radio Shack are made in the same factories as the resistors for Newark Electronics and such. The difference is, the tolerance rating. Radio Shack may be less likely to STOCK a 5% tolerance, but they could still order it.
Now, to the original question and tolerance. If you use a 22K R witha 10% tolerance, that can be anywhere from 20K to 24K. If you use two 10k R's with 10% tolerance, that can be anywhere from 18K to 22K.
In comparison, the original 20K resistor, if it had a tolerance of 10%, could be anywhere from 18K to 22K.
If you still have the original resistor, look at it to determine the tolerance. Look at the resistor and place the end where the color bands to the left. The fourth band from the left is the tolerance indicator:
A gold band will indicate +/- 5%
Silver is +/- 10%
An absence of either one will indicate +/- 20%
After you determine the tolerance, you can base your decision on how strict or close the tolerance was intended, or how important it is to be as close to 20K as required.
Paul