No, the last digit will become a zero -- following the usual rules of arithmetic. From the COBOL Language Reference (manuals link at the top of the page):
18.104.22.168 Alignment rules
The standard alignment rules for positioning data in an elementary item depend on the category of a receiving item (that is, an item into which the data is moved; see "Elementary moves" in topic 22.214.171.124).
For such receiving items, the following rules apply:
1. The data is aligned on the assumed decimal point and, if necessary, truncated or padded with zeros. (An assumed decimal point is one that has logical meaning but that does not exist as an actual character in the data.)
2. If an assumed decimal point is not explicitly specified, the receiving item is treated as though an assumed decimal point is specified immediately to the right of the field. The data is then treated according to the preceding rule.