Does SSL port 443 provide true anonymity?
Your idea of VPNs is a bit wrong. Please read up on that.
What's the different between connecting on TCP/UDP port 443 vs SSL 443?
TCP/443 is used by HTTPS. Looking at IT networks around the world, it's less likely being filtered.
UDP/443 doesn't have this advantage, but OpenVPN usually performs better on UDP.
SSL/443 is essentially TCP/443 with a SSL layer on top of OpenVPN. The advantage is that clients looking at your connection between your computer and the VPN server (someone on your LAN, your ISP, etc.) will see a SSL connection if they analyze it. The downside is more encryption/decryption effort on your computer and the VPN server. Also, the overhead is bigger, leading to a small additional loss of throughput ("speed").
If I do SSL port 443 is there really no way that my ISP can know I'm using a VPN at all and will just come across as normal HTTPS traffic?
You can test it yourself. Use whoer.net or the WITCH script (currently a bit broken, though).