According to my extremely limited understanding, yes. If I'm wrong, I'm sure there is no shortage of members here to jump in and excoriate me.
You're right. Vanguard's fund that targets 2055, which they recommend for someone born 1988-1992, has the following allocation:
Vanguard Total Stock Market Index Fund Investor Shares 54.20%
Vanguard Total International Stock Index Fund Investor Shares 36.30%
Vanguard Total Bond Market II Index Fund Investor Shares† 6.50%
Vanguard Total International Bond Index Fund Investor Shares 1 2.90%
Vanguard Total International Bond II Index Fund 0.10%
https://investor.vanguard.com/mutual-funds/profile/VFFVXThe total stock market is made up of >3000 companies, of which about 500 (surprise!) make up the S&P 500, which can be invested in with S&P 500 funds/ETFs such as SPY or VOO (or others). These 500 are the large companies, and make up about 75% of the Total Stock Market Index. So 75% of 54% means that about 40% of your investment would be in a VOO-equivalent, and there's no need to invest in VOO separately.
(As I understand it, also not an expert in this. Or anything, but that's another story.)