Technically, yes. Jews who keep the Mosaic covenant (aka The Law) perfectly, as presented by God through Moses, can most definitely make it to heaven without Yeshua. If they have no sin, they have no need for the sacrifice that atones for sin. But there is a major problem:
Sin can be summarized as threefold:
1. An act, the violation or want of obedience to the revealed will of God
2. A state or absence of righteousness
3. A nature that has antagonism toward God
Every person – Jewish or non-Jewish – has missed the mark of God’s righteousness. That means that no one alive, Jew or Gentile, falls into that category of God’s profection, so the truth stands that a person must be made perfect in order to see God. How can that be done?
According to the Mosaic covenant, man would be made right before God through the sacrificing of an animal, but there is another problem:
Since there is currently no tabernacle or temple to do these sacrifices in, then trying to approach God by this covenant leaves you with your sin. With no way to atone for your sins according to the Mosaic covenant, Jews need the atonement Yeshua offers just as much as every person in the world. It is written in Romans 3:23 “For all have sinned and fallen short of the Glory of God”