Hilchos Issurei Mizbeiach 6:15

All flour offerings and libations are valid both from produce grown in Israel and from produce grown elsewhere. They are valid whether brought from the current year's produce of from earlier years' produce so long as it is of premium quality. The exceptions to these rules are the omer of barley and the two loaves offered on Shavuos, which must be of the current year's grain grown in Israel.

Hilchos Issurei Mizbeiach 7:1

Just because something isn’t unfit for the altar, that doesn’t mean it should necessarily be brought as an offering. For example, a person who has to bring a burnt offering shouldn’t bring a weak and ugly sheep, justifying that it’s unblemished. Regarding such an attitude, Malachi 1:14 says, “Cursed be the charlatan…” (the verse continues that he vows an offering to God and then brings one of inferior quality). Rather, one who brings an offering must bring items of the highest quality.