all computer monitors are different and seldom show the same colors as the next one...if you are concerned about matching i would contact the shop and ask for a swatch of the questionable fabrics so i can see how they are together. my favorite on-line fab shops offer swatch services. usually will put in requested swatches for about 75 cents each.
dye lots change with continued (manufacturing runs) so there at times can be change. request samples if it is imperitive that the fabric matches