No, that implication is not automatic. The Babylonian numeral system evolved over milenaries, and the simple space noting the absence of a digit between two digits was later noted by a "0" digit. But this symbol was never used by itself, so it did not mean "nothingness". In the same way, a civilization having the concepts of addition and subtraction does not automatically induce the concept of negative numbers.
On the other side, ancient Egyptian numerals did have a zero, but it was only for nothingness. But they did not have a placeholder zero, because their systems was similar to Greek and Roman numerals.
No, that implication is not automatic. The Babylonian numeral system evolved over milenaries, and the simple space noting the absence of a digit between two digits was later noted by a "0" digit. But this symbol was never used by itself, so it did not mean "nothingness". In the same way, a civilization having the concepts of addition and subtraction does not automatically induce the concept of negative numbers.
On the other side, ancient Egyptian numerals did have a zero, but it was only for nothingness. But they did not have a placeholder zero, because their systems was similar to Greek and Roman numerals.